At 9:54 Paul Drake parks his car and walks across the street to The Sunset bar. The window has alarm tape along the bottom. But when a switch is made to a close-up at 9:56, the tape is missing. Presumably they cut to a studio set as the cut that follows shows Arnel and Tommy arguing in front of a very obvious rear-screen projection.
When the body of Victor Bundy is found lying by the fireplace, the camera hangs on actor Jacques Aubuchon during the fade long enough to see his eyes move under their lids, unusual activity for a supposed corpse.
When Perry begins presenting his client's case, "sunlight" is shining through a window in the courtroom, leaving a shadow of its frame and woodwork on the back wall. The "sunlight" and shadow do not move despite considerable time passing as Perry examines several witnesses. Thus it is clear that actual sunlight is not shining through the window.
Although the true identity of Sue Randall's character is known for most of the episode (Arnell Stiller), including the preliminary hearing, her character is identified in the credits only by the alias she used (Amy Scott).
When Perry picks up the phone in Bundy's apartment to call homicide, he handles the phone barehanded, thus leaving his fingerprints on it -- something he usually avoids doing.
When Paul sits down at the hotel bar with Joyce Carlton, she has a drink, a pack of cigarettes and a book of matches in front of her (and she has a lit cigarette in her hand), yet after Paul investigates the book of matches and Mr. Kern arrives, she and Kern depart but she leaves the cigarettes and matchbook on the bar.